426 a placebo (vitamin B). She was told that she had a cardiac neurosis and she became increasingly depressed and frustrated that doctors did not accept that her symptoms were genuine. She became agoraphobic in 1977; she would not walk in the street for fear of a heart-attack, and would take a taxi to work in her fruit shop only 200 yards away. At this stage she was referred to our clinic. Her dietary history revealed that she drank vast quantities of tea (she described herself as a "tea fiend") and she was admitted for tests. Water, tea, coffee, and tomato were given via a nasogastric tube (so that the patient would not know what substance was being given) on different days while the patient was connected to a cardiac monitor. A supraventricular tachycardia (rate 160 per min) and the symptoms she had described occurred about 2thours after tea, coffee, or tomato, but not after water. Since avoiding tea, coffee, and tomatoes she has had no symptoms and now, 6 months later, is no longer agoraphobic, is working in her shop, and leading a normal social life.
by
Controversy "FOOD ALLERGY": FACT OR FICTION? RONALD FINN
H. NEWMAN COHEN
Royal Southern Hospital, Liverpool L8 5SH, and Department of Medicine, University of Liverpool Six patients with longstanding physical and mental symptoms who had not been helped by many years of conventional medical investigation and treatment experienced immediate relief of symptoms when they avoided certain foodstuffs. This clinical study supports the view that some foods may cause widespread and disabling symptoms in people who are sensitive to them.
Summary
INTRODUCTION
IT has been claimed that many symptoms, such
as
headache, palpitations, vomiting, panic attacks, and anxiety can be due to "food allergy",’ the term allergy
being used in its original, broader sense to imply altered reactivity and not cellular or humoral immunity. This wider concept of food allergy has been propounded over many years in the United States,2 but has never been accepted by the majority of the medical profession; little or no reference is made to food allergy in standard meditextbooks, and even a recent American text on this subject is written largely by authors from outside the major medical schools.3 cal
Since many diseases are caused by the interaction of with the environment, and since one of the major environmental contacts is food, it seems feasible that dietary factors may cause disease; moreover the longterm influence of diet on diseases such as arteriosclerosis and diverticulosis is widely accepted. We have tried to find objective evidence for the suggestion that many patients, in whom a precise diagnosis cannot be made and who are not helped by conventional treatments, have an unrecognised food allergy.4 We describe our preliminary findings in six patients in whom extensive investigations and prolonged medical treatment had failed to effect any improvement, but in whom dietary restriction led to a dramatic cessation of symptoms. man
CASE-REPORTS
CaseI
aged 37, presented in 1973 with episodes few minutes) of pain below the left breast associated (lasting with palpitations and dyspnoea. A diagnosis of pulmonary embolism was made and she was given heparin and ’Warfarin’ but when a lung scan and chest X-ray turned out to be normal, the diagnosis was changed to that of effort syndrome. She was discharged on practolol 100 mg twice daily but, she stopped. taking this of her own accord when symptoms improved over the ensuing months. In 1976 she saw a cardiologist for the same symptoms but, in addition, had become extremely anxious. Her mother had died from a heart-attack and the patient was terrified that the same fate would befall her. No organic heart-lesion could be found. She was treated with sotolol, but this was later replaced A married woman, a
Case II A man aged 26 came to the neurological clinic in 1976 with throbbing, mainly occipital, headaches which he had had for many years, and which were becoming more severe. He would feel sick with the pain, dreaded going to bed because of the headache, and would sit up playing patience for most of the night; he felt his speech was a little slurred, and that his right leg would drag. He gave up his work because of the headache. Neurological examination revealed brisk reflexes, and some possible sensory loss over the right leg. Skull X-ray, electroencephalogram, brain-scan, and an air-encephalogram were normal. A diagnosis of migraine was made, but in spite of conventional drug treatment his symptoms continued. A psychiatrist concluded that his symptoms were largely caused by anxiety over his wife’s impending confinement. He continued to have headaches and, in 1976, noticed urgency of micturition and pain radiating down the spine. Further neurological examination revealed that his reflexes had become more brisk and that he had an equivocal right extensor plantar response. He was readmitted to hospital for a brainscan which was normal. Another electroencephalogram suggested a possible abnormality in the left parietal region but his carotid angiogram was normal. An intravenous pyelogram was also normal. A psychiatrist was asked to reassess him. The patient had by this time been unable to work for some years and was almost completely house-bound. At this stage the patient’s wife, who was certain that there was an organic basis for his condition, demanded a second opinion. We found that the patient was drinking more than 20 cups of coffee a day and advised him to give it up completely. His headaches and other symptoms promptly resolved, he has remained symptomless for the last 6 months, and he has been able to set up business again.
Case III A girl, aged 13, had had aphthous ulcers since infancy. She also had ulcers in the vagina. The ulcers were both large and extremely painful and she had never been free of symptoms for more than 3 weeks. She had received many treatments throughout her life, but none had been successful. Drug therapy had included metronidazole, hydrocortisone (’Corlan’) pellets, cromoglycate, prednisolone, furazolidone, levamisole and ferrous sulphate (’Ferro-Gradumet’), all ineffective. Many investigations (including barium studies and a jejunal biopsy)
negative. By the age of
were
12 the patient was extremely depressed and frustrated because of her chronic pain. She was missing school and becoming a difficult child. She was eventually investigated for food allergy. In the ward, on a meat-and-water diet, only one fresh ulcer developed in 3 weeks. Her mother noticed a great improvement in her personality and general behaviour. When various foods were added sequentially, she was found
427 be sensitive to potato, ttffee, and chocolate. After withdrawal of these agents the aphthous ulcers resolved and she has been completely free of ulcers for 4 months. We subsequently learnt that for most of her life she had eaten raw potato almost daily. to
Case IV A man, aged 20, had a 3-year history of attacks of severe pain in the right iliac fossa which would last for up to 3 days.
pain, which was not associated with other abdominal symptoms, prevented him from concentrating on his university studies. Once, the pain was so severe that he was admitted to The
hospital for suspected renal colic,
but investigations, including intravenous pyelogram, were negative. Since the patient suspected that his pain was due to alcohol (he had noticed that with abstention from alcohol the pain came on less frequently) or to tea, he was admitted for food-allergy tests. The patient was given, on different occasions, in irregular sequence, water and tea via a nasogastric tube. Each was given five times and each time tea was given, he had a tachycardia with abdominal pain appearing the next day. The probability that these events could occur by chance is 1 in 1024. No reaction occurred with water, but alcohol, given once, produced a similar response to tea. Since giving up tea and alcohol 4 months ago, he has had no discomfort. an
Case V An unmarried
woman aged 32, who described herself as been a "sickly child", had had nausea and vomiting since childhood. She had been regularly given anti-emetics, which were rarely effective. As a teenager she had noticed that her fingers would occasionally swell and that her eyes would feel gritty. When she was not actually vomiting she would have constant nausea. At one stage she had been seen in an allergy clinic where patch tests were carried out, but no conclusion was drawn. The patient felt that foods might be responsible for her plight; she preferred a vegetarian diet, although she still required large doses of antihistamines throughout the day to prevent vomiting in public. She had restricted her social life because she had occasionally vomited at table when eating out. She became depressed and lethargic and lost her normal zest for life; her activities were grossly restricted by travel sickness with any form of transport (a 2-hour car journey would necessitate numerous stops); and her relation with her fiancee was strained because she was becoming short-tempered and losing her libido as a result of her constant nausea. She was first seen at the neurological clinic when she fainted and her general practitioner wished epilepsy to be excluded. There was no evidence of neurological disease, but the faint had been associated with a short bout of palpitations occurring shortly after a cup of tea. She was, therefore, admitted for food-allergy assessment. On the basis of her dietary history, tea was excluded from her diet and the vomiting and nausea ceased. Later, tea or water was given in irregular sequence on different days via a nasogastric tube. On each of the five occasions that tea was introduced, vomiting occurred within 30 minutes. The probability of such a response occurring by chance is only 1 in 1024. No response occurred with any of the five water challenges. By avoiding tea she has been symptomless for 5 months, does not take drugs, and is able to travel long distances by car without feeling sick. She has recently married and is pregnant.
having
Case VI A man aged 44, was treated for essential hypertension in 1970. He was symptomless and remained well on a thiazide diuretic until 1974 when he had chest pain, sweating,’faintness, sickness, and a general feeling of panic. He was admitted to hospital for a possible coronary thrombosis, but this was not
was discharged after 5 days. After this he lost all interest in life, was unable to work lethargic, a and became regular defaulter from work in the garproperly, age he managed. In 1975 he received 20 sessions of hypnosis followed shortly afterwards by 13 electroconvulsive treatments but remained as tired and anxious as ever and began to have suicidal thoughts. He was seen by us for a second opinion on his blood-pressure which had become difficult to control at 210/125 mm Hg. The possibility of phecochromocytoma was excluded, but he was found to have a renal-artery stenosis; after surgical treatment for the renal-artery stenosis, his blood-pressure became normal. Unfortunately his mental symptoms persisted and he was still unable to work; he took vast doses of tranquillisers throughout the day. At this stage a dietary history revealed that he drank tea and coffee frequently throughout the day. On avoiding foods and drinks containing caffeine he began to feel better within 3 days. Since then all symptoms of panic, lethargy, depression, faintness, and sweating have regressed completely, and he is back at work.
confirmed, and he became
DISCUSSION
There is always a hard core of patients (such as those have described) in whom no conclusive diagnosis can be made and who seem refractory to all forms of therapy. We aimed to test the theory that sensitivity to food could be the cause of symptoms in this type of patient. We are aware of the difficulty of measuring many of our patients’ symptoms and we have, therefore, attempted to obtain objective evidence wherever possible. Cases I, III, and V had objective signs of disease. The development of a supraventricular tachycardia after provocation with tea, coffee, and tomato is striking. Tea and coffee are known to precipitate arrhythmias, but the induction of supraventricular tachycardia with tea, coffee, and tomato under controlled experimental conditions has not, to our knowledge, been reported. For cases IV and V we present statistical evidence in favour of a causal relationship between a particular food and the production of symptoms. Cases II and IV had only subjective symptoms and we rely on the immediacy of the cure to support the theory. The long history and many treatments attempted in these cases, makes it very unlikely that the relief of symptoms obtained simultaneously with alteration in diet is a fortuitous occurwe
rence.
the psychological symptoms had. These we, feel were partly due to frustration and fear because their doctors were unable to effect a cure or even, in some cases, to believe that their symptoms were genuine. It is also possible that the food which the patient is unable to tolerate may produce mental symptoms, and it is interesting to note that organic cerebral damage can occur in migraine,6a condition which can be brought on by certain foods. This concept that food is able to produce mental disease is new,4 and perhaps hard to accept, but less so if one considers that alcohol can cause mental symptoms. We wish to stress that our patients were ill for several years during which time they underwent numerous investigations and treatments, some of which were potentially dangerous; most patients had also required hospital admissions. Tea and coffee appear to be incriminated disproportionately frequently in our patients. The symptoms produced by excessive coffee are probably due to caffeine; We
our
were
patients
impressed by
428 the symptoms, whicn may mimic an anxiety state, include irritability, palpitations, headache, and gastrointestinal disturbances. Although these reactions to coffee have been well documented,7.8 it is clear that the diagnosis is often overlooked. Intolerance to carbohydrate has also been commonly reported in America; we have seen two further cases which responded to withdrawal of a carbohydrate. Unlike conventional allergic reactions, such as a skin rash, the patient is usually unaware of the food to which he is sensitive and may even be unaware that his symptoms might be due to food intolerance. The offending agent is often a favourite food which is taken daily, usually in large quantities. We would stress again that the term food allergy in this context is used in its original sense to mean unusual response to a common sub-
Public Health SUSCEPTIBILITY TO DIPHTHERIA A SURVEY BY AN AD-HOC WORKING
GROUP*
Schick tests and antitoxin titrations have been carried out to investigate what percentage of individuals in each of 9 small groups
Summary
susceptible to diphtheria. Overall, 33% were susceptible: 26% among those below and 44% among those were
above 35 years of age. These results suggest that about 35% of the population of the United Kingdom are sus-
ceptible to diphtheria. INTRODUCTION
DURING the five years 1971-75 there were in England and Wales 37 notifications of diphtheria (including 2 deaths). Each notification implied an individual with insufficient diphtheria antitoxin to protect against an eminently preventable infection and so emphasised that, even in a community in which immunoprophylaxis is * Members: J. V. DADSWELL, Director, Public Health Laboratory, Reading; D. F. ROWLANDS, Deputy Director, University Health Service, Reading University; F. W. SHEFFIELD, Head, Division of Bacterial Products, National Institute for Biological Standards and Con-
trol, London; J. W. G. SMITH, Director, National Institute for Biological Standards and Control, London; PATRICIA J. WHERRY, Epidemiological Research Laboratory, Public Health Laboratory Service, Colindale; W. G. WHITE, Senior Medical Officer, British Leyland, Oxford.
stance. The most likely possibility is that patients with food allergy have some degree of enzyme deficiency, which leads to difficulty in metabolising certain foods; and it is the consequent build-up of intermediate metabolites which causes toxic symptoms.
REFERENCES 1.
Randolph,
T. G. Human
Ecology
and
Susceptibility to the Chemical Envir-
onment; Springfield, Illinois, 1962. 2. Rowe, A. H. Food Allergy, Its Manifestations,
Philadelphia, 1931. 3. Dickey, L. D. (editor)
Diagnosis,
in Clinical Ecology. Springfield, 4. Mackarness, R. Not All in the Mind. London, 1976. 5. Bernstein, C., Klotz, S. D. Ann. Allergy, 1950, 8, 336. 6. Mathew, N. T., Meyer, J. S., Welch, K. M. A., and minerva Medica 1977, 19, 179. 7. Br. med. J. 1975, i, 296. 8. Greden, J. F. Am. J. Psychiat. 1974, 131, 1089.
and Treatment.
Illinois,
1976.
Neblett,
C. P. Pan-
freely available, a proportion of the population remains unprotected. The size of this proportion, although of considerable epidemiological interest, cannot be estimated with precision because of the difficulty of obtaining a large, representative vertical sample of the population either for Schick testing or for antitoxin titration. However, during the last two years, 9 small groups, consisting of a total of 771 individuals, became available for Schick testing or for estimation of diphtheria antitoxin titres. Although, individually, they are unrepresentative of the population as a whole, they may, when combined, constitute an informative sample. METHODS
The 9 groups were drawn from nine communities within each of which members showed common educational, vocational, or residential backgrounds. 5 of the groups consisted of individuals who had agreed to be Schick tested and 4 were of individuals from whom venous blood-samples had been obtained for various immunological investigations. The sources from which the 9 groups were drawn are recorded in table i. Schick testing was done in the orthodox manner. Both specific and non-specific (pseudo) reactions to the test-toxin and control were recorded but for this report the non-specific reactions have been excluded and all results are expressed as either Schick positive or Schick negative. Antitoxin assays were done on sera separated from the venous blood-samples. An in-vitro micro-method based on the neutralisation of the toxicity of diphtheria toxin for cell cultures was used.l,2 Each 0-2 ml of toxin-antitoxin mixture contained two minimum cell-culture toxic doses of diphtheria toxin, a measure of one of a series of doubling dilutions of test serum, and an inoculum of 5000 hela cells. The third British
TABLE I--GROUPS TESTED FOR SUSCEPTIBILITY TO DIPHTHERIA
by
Controversy "FOOD ALLERGY": FACT OR FICTION? RONALD FINN
H. NEWMAN COHEN
Royal Southern Hospital, Liverpool L8 5SH, and Department of Medicine, University of Liverpool Six patients with longstanding physical and mental symptoms who had not been helped by many years of conventional medical investigation and treatment experienced immediate relief of symptoms when they avoided certain foodstuffs. This clinical study supports the view that some foods may cause widespread and disabling symptoms in people who are sensitive to them.
Summary
INTRODUCTION
IT has been claimed that many symptoms, such
as
headache, palpitations, vomiting, panic attacks, and anxiety can be due to "food allergy",’ the term allergy
being used in its original, broader sense to imply altered reactivity and not cellular or humoral immunity. This wider concept of food allergy has been propounded over many years in the United States,2 but has never been accepted by the majority of the medical profession; little or no reference is made to food allergy in standard meditextbooks, and even a recent American text on this subject is written largely by authors from outside the major medical schools.3 cal
Since many diseases are caused by the interaction of with the environment, and since one of the major environmental contacts is food, it seems feasible that dietary factors may cause disease; moreover the longterm influence of diet on diseases such as arteriosclerosis and diverticulosis is widely accepted. We have tried to find objective evidence for the suggestion that many patients, in whom a precise diagnosis cannot be made and who are not helped by conventional treatments, have an unrecognised food allergy.4 We describe our preliminary findings in six patients in whom extensive investigations and prolonged medical treatment had failed to effect any improvement, but in whom dietary restriction led to a dramatic cessation of symptoms. man
CASE-REPORTS
CaseI
aged 37, presented in 1973 with episodes few minutes) of pain below the left breast associated (lasting with palpitations and dyspnoea. A diagnosis of pulmonary embolism was made and she was given heparin and ’Warfarin’ but when a lung scan and chest X-ray turned out to be normal, the diagnosis was changed to that of effort syndrome. She was discharged on practolol 100 mg twice daily but, she stopped. taking this of her own accord when symptoms improved over the ensuing months. In 1976 she saw a cardiologist for the same symptoms but, in addition, had become extremely anxious. Her mother had died from a heart-attack and the patient was terrified that the same fate would befall her. No organic heart-lesion could be found. She was treated with sotolol, but this was later replaced A married woman, a
Case II A man aged 26 came to the neurological clinic in 1976 with throbbing, mainly occipital, headaches which he had had for many years, and which were becoming more severe. He would feel sick with the pain, dreaded going to bed because of the headache, and would sit up playing patience for most of the night; he felt his speech was a little slurred, and that his right leg would drag. He gave up his work because of the headache. Neurological examination revealed brisk reflexes, and some possible sensory loss over the right leg. Skull X-ray, electroencephalogram, brain-scan, and an air-encephalogram were normal. A diagnosis of migraine was made, but in spite of conventional drug treatment his symptoms continued. A psychiatrist concluded that his symptoms were largely caused by anxiety over his wife’s impending confinement. He continued to have headaches and, in 1976, noticed urgency of micturition and pain radiating down the spine. Further neurological examination revealed that his reflexes had become more brisk and that he had an equivocal right extensor plantar response. He was readmitted to hospital for a brainscan which was normal. Another electroencephalogram suggested a possible abnormality in the left parietal region but his carotid angiogram was normal. An intravenous pyelogram was also normal. A psychiatrist was asked to reassess him. The patient had by this time been unable to work for some years and was almost completely house-bound. At this stage the patient’s wife, who was certain that there was an organic basis for his condition, demanded a second opinion. We found that the patient was drinking more than 20 cups of coffee a day and advised him to give it up completely. His headaches and other symptoms promptly resolved, he has remained symptomless for the last 6 months, and he has been able to set up business again.
Case III A girl, aged 13, had had aphthous ulcers since infancy. She also had ulcers in the vagina. The ulcers were both large and extremely painful and she had never been free of symptoms for more than 3 weeks. She had received many treatments throughout her life, but none had been successful. Drug therapy had included metronidazole, hydrocortisone (’Corlan’) pellets, cromoglycate, prednisolone, furazolidone, levamisole and ferrous sulphate (’Ferro-Gradumet’), all ineffective. Many investigations (including barium studies and a jejunal biopsy)
negative. By the age of
were
12 the patient was extremely depressed and frustrated because of her chronic pain. She was missing school and becoming a difficult child. She was eventually investigated for food allergy. In the ward, on a meat-and-water diet, only one fresh ulcer developed in 3 weeks. Her mother noticed a great improvement in her personality and general behaviour. When various foods were added sequentially, she was found
427 be sensitive to potato, ttffee, and chocolate. After withdrawal of these agents the aphthous ulcers resolved and she has been completely free of ulcers for 4 months. We subsequently learnt that for most of her life she had eaten raw potato almost daily. to
Case IV A man, aged 20, had a 3-year history of attacks of severe pain in the right iliac fossa which would last for up to 3 days.
pain, which was not associated with other abdominal symptoms, prevented him from concentrating on his university studies. Once, the pain was so severe that he was admitted to The
hospital for suspected renal colic,
but investigations, including intravenous pyelogram, were negative. Since the patient suspected that his pain was due to alcohol (he had noticed that with abstention from alcohol the pain came on less frequently) or to tea, he was admitted for food-allergy tests. The patient was given, on different occasions, in irregular sequence, water and tea via a nasogastric tube. Each was given five times and each time tea was given, he had a tachycardia with abdominal pain appearing the next day. The probability that these events could occur by chance is 1 in 1024. No reaction occurred with water, but alcohol, given once, produced a similar response to tea. Since giving up tea and alcohol 4 months ago, he has had no discomfort. an
Case V An unmarried
woman aged 32, who described herself as been a "sickly child", had had nausea and vomiting since childhood. She had been regularly given anti-emetics, which were rarely effective. As a teenager she had noticed that her fingers would occasionally swell and that her eyes would feel gritty. When she was not actually vomiting she would have constant nausea. At one stage she had been seen in an allergy clinic where patch tests were carried out, but no conclusion was drawn. The patient felt that foods might be responsible for her plight; she preferred a vegetarian diet, although she still required large doses of antihistamines throughout the day to prevent vomiting in public. She had restricted her social life because she had occasionally vomited at table when eating out. She became depressed and lethargic and lost her normal zest for life; her activities were grossly restricted by travel sickness with any form of transport (a 2-hour car journey would necessitate numerous stops); and her relation with her fiancee was strained because she was becoming short-tempered and losing her libido as a result of her constant nausea. She was first seen at the neurological clinic when she fainted and her general practitioner wished epilepsy to be excluded. There was no evidence of neurological disease, but the faint had been associated with a short bout of palpitations occurring shortly after a cup of tea. She was, therefore, admitted for food-allergy assessment. On the basis of her dietary history, tea was excluded from her diet and the vomiting and nausea ceased. Later, tea or water was given in irregular sequence on different days via a nasogastric tube. On each of the five occasions that tea was introduced, vomiting occurred within 30 minutes. The probability of such a response occurring by chance is only 1 in 1024. No response occurred with any of the five water challenges. By avoiding tea she has been symptomless for 5 months, does not take drugs, and is able to travel long distances by car without feeling sick. She has recently married and is pregnant.
having
Case VI A man aged 44, was treated for essential hypertension in 1970. He was symptomless and remained well on a thiazide diuretic until 1974 when he had chest pain, sweating,’faintness, sickness, and a general feeling of panic. He was admitted to hospital for a possible coronary thrombosis, but this was not
was discharged after 5 days. After this he lost all interest in life, was unable to work lethargic, a and became regular defaulter from work in the garproperly, age he managed. In 1975 he received 20 sessions of hypnosis followed shortly afterwards by 13 electroconvulsive treatments but remained as tired and anxious as ever and began to have suicidal thoughts. He was seen by us for a second opinion on his blood-pressure which had become difficult to control at 210/125 mm Hg. The possibility of phecochromocytoma was excluded, but he was found to have a renal-artery stenosis; after surgical treatment for the renal-artery stenosis, his blood-pressure became normal. Unfortunately his mental symptoms persisted and he was still unable to work; he took vast doses of tranquillisers throughout the day. At this stage a dietary history revealed that he drank tea and coffee frequently throughout the day. On avoiding foods and drinks containing caffeine he began to feel better within 3 days. Since then all symptoms of panic, lethargy, depression, faintness, and sweating have regressed completely, and he is back at work.
confirmed, and he became
DISCUSSION
There is always a hard core of patients (such as those have described) in whom no conclusive diagnosis can be made and who seem refractory to all forms of therapy. We aimed to test the theory that sensitivity to food could be the cause of symptoms in this type of patient. We are aware of the difficulty of measuring many of our patients’ symptoms and we have, therefore, attempted to obtain objective evidence wherever possible. Cases I, III, and V had objective signs of disease. The development of a supraventricular tachycardia after provocation with tea, coffee, and tomato is striking. Tea and coffee are known to precipitate arrhythmias, but the induction of supraventricular tachycardia with tea, coffee, and tomato under controlled experimental conditions has not, to our knowledge, been reported. For cases IV and V we present statistical evidence in favour of a causal relationship between a particular food and the production of symptoms. Cases II and IV had only subjective symptoms and we rely on the immediacy of the cure to support the theory. The long history and many treatments attempted in these cases, makes it very unlikely that the relief of symptoms obtained simultaneously with alteration in diet is a fortuitous occurwe
rence.
the psychological symptoms had. These we, feel were partly due to frustration and fear because their doctors were unable to effect a cure or even, in some cases, to believe that their symptoms were genuine. It is also possible that the food which the patient is unable to tolerate may produce mental symptoms, and it is interesting to note that organic cerebral damage can occur in migraine,6a condition which can be brought on by certain foods. This concept that food is able to produce mental disease is new,4 and perhaps hard to accept, but less so if one considers that alcohol can cause mental symptoms. We wish to stress that our patients were ill for several years during which time they underwent numerous investigations and treatments, some of which were potentially dangerous; most patients had also required hospital admissions. Tea and coffee appear to be incriminated disproportionately frequently in our patients. The symptoms produced by excessive coffee are probably due to caffeine; We
our
were
patients
impressed by
428 the symptoms, whicn may mimic an anxiety state, include irritability, palpitations, headache, and gastrointestinal disturbances. Although these reactions to coffee have been well documented,7.8 it is clear that the diagnosis is often overlooked. Intolerance to carbohydrate has also been commonly reported in America; we have seen two further cases which responded to withdrawal of a carbohydrate. Unlike conventional allergic reactions, such as a skin rash, the patient is usually unaware of the food to which he is sensitive and may even be unaware that his symptoms might be due to food intolerance. The offending agent is often a favourite food which is taken daily, usually in large quantities. We would stress again that the term food allergy in this context is used in its original sense to mean unusual response to a common sub-
Public Health SUSCEPTIBILITY TO DIPHTHERIA A SURVEY BY AN AD-HOC WORKING
GROUP*
Schick tests and antitoxin titrations have been carried out to investigate what percentage of individuals in each of 9 small groups
Summary
susceptible to diphtheria. Overall, 33% were susceptible: 26% among those below and 44% among those were
above 35 years of age. These results suggest that about 35% of the population of the United Kingdom are sus-
ceptible to diphtheria. INTRODUCTION
DURING the five years 1971-75 there were in England and Wales 37 notifications of diphtheria (including 2 deaths). Each notification implied an individual with insufficient diphtheria antitoxin to protect against an eminently preventable infection and so emphasised that, even in a community in which immunoprophylaxis is * Members: J. V. DADSWELL, Director, Public Health Laboratory, Reading; D. F. ROWLANDS, Deputy Director, University Health Service, Reading University; F. W. SHEFFIELD, Head, Division of Bacterial Products, National Institute for Biological Standards and Con-
trol, London; J. W. G. SMITH, Director, National Institute for Biological Standards and Control, London; PATRICIA J. WHERRY, Epidemiological Research Laboratory, Public Health Laboratory Service, Colindale; W. G. WHITE, Senior Medical Officer, British Leyland, Oxford.
stance. The most likely possibility is that patients with food allergy have some degree of enzyme deficiency, which leads to difficulty in metabolising certain foods; and it is the consequent build-up of intermediate metabolites which causes toxic symptoms.
REFERENCES 1.
Randolph,
T. G. Human
Ecology
and
Susceptibility to the Chemical Envir-
onment; Springfield, Illinois, 1962. 2. Rowe, A. H. Food Allergy, Its Manifestations,
Philadelphia, 1931. 3. Dickey, L. D. (editor)
Diagnosis,
in Clinical Ecology. Springfield, 4. Mackarness, R. Not All in the Mind. London, 1976. 5. Bernstein, C., Klotz, S. D. Ann. Allergy, 1950, 8, 336. 6. Mathew, N. T., Meyer, J. S., Welch, K. M. A., and minerva Medica 1977, 19, 179. 7. Br. med. J. 1975, i, 296. 8. Greden, J. F. Am. J. Psychiat. 1974, 131, 1089.
and Treatment.
Illinois,
1976.
Neblett,
C. P. Pan-
freely available, a proportion of the population remains unprotected. The size of this proportion, although of considerable epidemiological interest, cannot be estimated with precision because of the difficulty of obtaining a large, representative vertical sample of the population either for Schick testing or for antitoxin titration. However, during the last two years, 9 small groups, consisting of a total of 771 individuals, became available for Schick testing or for estimation of diphtheria antitoxin titres. Although, individually, they are unrepresentative of the population as a whole, they may, when combined, constitute an informative sample. METHODS
The 9 groups were drawn from nine communities within each of which members showed common educational, vocational, or residential backgrounds. 5 of the groups consisted of individuals who had agreed to be Schick tested and 4 were of individuals from whom venous blood-samples had been obtained for various immunological investigations. The sources from which the 9 groups were drawn are recorded in table i. Schick testing was done in the orthodox manner. Both specific and non-specific (pseudo) reactions to the test-toxin and control were recorded but for this report the non-specific reactions have been excluded and all results are expressed as either Schick positive or Schick negative. Antitoxin assays were done on sera separated from the venous blood-samples. An in-vitro micro-method based on the neutralisation of the toxicity of diphtheria toxin for cell cultures was used.l,2 Each 0-2 ml of toxin-antitoxin mixture contained two minimum cell-culture toxic doses of diphtheria toxin, a measure of one of a series of doubling dilutions of test serum, and an inoculum of 5000 hela cells. The third British
TABLE I--GROUPS TESTED FOR SUSCEPTIBILITY TO DIPHTHERIA
